Various soil release agents have been suggested for use in detergent compositions in order to enhance grease and oil cleaning of detergent compositions for synthetic fibers and fabrics. Synthetic textiles, such polyesters, polyacrylamides (e.g. nylon), and acrylics typically have hydrophobic surfaces which make removal of grease- and oil-type stains difficult. Soil release agents are compounds having both hydrophobic and hydrophilic sections. The hydrophobic portion of the soil release agent adheres to the surfaces of the synthetic fibers or fabric, and the hydrophilic portion of the soil release agent increases hydrophilicity of the surface of the synthetic material. Once deposited, these soil release agents enhance cleaning ability of detergents in subsequent washings since grease and oil are more easily removed from the hydrophilized fabric surface.
Unfortunately, other components present in detergent compositions, especially anionic materials such as anionic detersive surfactants and builder salts, can interfere with soil release agent performance and, hence, impair overall cleaning ability of the detergent.
The formulator of liquid detergent compositions can face an especially difficult challenge because the type of soil release agent best suited for liquid detergents typically are characterized by having nonionic hydrophile sections (which typically comprise ethoxylate monomeric units) that have a strong propensity to interact with anionic surfactants.
Detergent compositions can be easily prepared which do not include surfactant systems that significantly interact with soil release agents by eliminating or severely reducing the level of anionic surfactant present in the formulation. However, the presence of anionic surfactants is often highly desirable in detergent compositions for superior cleaning ability across a broad spectrum of stains. Conventional nonionic surfactants can be added to the composition to assist in overall detergency performance, however it remains desirable to provide compositions containing anionic surfactants and soil release agents which have both enhanced soil release agent efficiency and improved overall detergent performance, especially improved grease/oil cleaning ability.
Accordingly, there is a need for developing detergent compositions containing anionic surfactants and soil release agents that can provide improved detergency performance.